How do you get polarized charged particles?

In summary: So, you mean the synchrotron radiation can polarize the protons directly?Yes, you can use synchrotron radiation to polarize protons.
  • #1
BillKet
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Hello! how does one produced big ensembles of polarized charged particles (electrons, protons, muons etc.) for certain experiments? In the case of neutral particles (for example the nucleus in an atom) this could be done using a magnetic field, but I guess this won't work that straightforward with charged particles, as they would be affected by the Lorentz force. Thank you!
 
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  • #2
Depends on the particle. Electrons can be polarized by synchrotron radiation. Protons are normally polarized using atomic physics and the polarization preserved during acceleration. Antiprotons are produced via anti-Lambda decay.
 
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  • #3
Muons are produced polarized from pion decays (see e.g. the g-2 experiments).
 
  • #4
Vanadium 50 said:
Depends on the particle. Electrons can be polarized by synchrotron radiation. Protons are normally polarized using atomic physics and the polarization preserved during acceleration. Antiprotons are produced via anti-Lambda decay.
Thanks! What exactly do you mean by "by synchrotron radiation"?
 
  • #6
Vanadium 50 said:
I meant, how can you use synchrotron radiation to polarize electrons? Would any polarized light source work (e.g. a laser)? Or is there something special about the synchrotron radiation?
 
  • #8
To get polarized pritions, you can do it the following way. First, the hydrogen hydrogen ground state has two levels that come from adding the proton and electron spins: The F=1 state which is 3-fold degenerate and the F=0 singlet state. So first, you start with H2 and dissociate it into atomic hydrogen and pass the atomic hydrogen through a nonuniform magnetic field. This spilts the F=0 and F=1 state into 4 components and since the electron magnetic moment is stronger, 2 of the 4 states are eliminated and the other passes through. However, what you have now is a beam with the electrons in the same spin direction, but the proton in different spin orientations, which is not what you want.

So, the next thing you do is pass the beam through a radio frequency "tansition unit" (which also has a magnetic field to keep the spins aligned) which flips the spins of the electron and proton so that now the protons are spin aligned and the electrons are not. The last thing you do is strip off the electrons and you are left with a polarized proton beam.
 
  • #9
Except that you need to accelerate H- before stripping the electrons.
 
  • #10
H- never enters the picture in this case. Up until the neutral hydrogen is ionized, the hydrogen is essentially moving at thermal velocities or more accurately, the velocity it attains by moving from a low pressure region (1 psi absolute into vacuum through a nozzle. There are other types of polarized sources, but this is the type of which I am most familiar.
 
  • #11
In high energy accelerators, H- ions are accelerated in linear boosters that feed circular machines that carry protons. This is for the injection, where the injection trajectory is not the same as the orbit previously injected protons are on. Normally a thin foil does the stripping.
 
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  • #12
Ok, that is a method I am not familiar with. I am familiar with atomic ground state sources.
 

1. How do you create polarized charged particles?

To create polarized charged particles, a process called polarization must be used. This involves subjecting the particles to an external electric field, which causes them to align in a particular direction. This results in the particles having a net charge and becoming polarized.

2. What types of particles can be polarized?

Any particle with an electric charge can be polarized. This includes electrons, protons, and even larger particles such as atoms and molecules.

3. Why are polarized charged particles important in scientific research?

Polarized charged particles are important in scientific research because they can be used to study the behavior of electric and magnetic fields, as well as interactions between particles. They also have practical applications in technologies such as particle accelerators and medical imaging.

4. How do you measure the polarization of charged particles?

The polarization of charged particles can be measured using a device called a polarimeter. This instrument measures the direction and strength of the electric field created by the polarized particles.

5. Can polarized charged particles be used in everyday life?

While polarized charged particles are primarily used in scientific research and technology, they do have some everyday applications. For example, polarized particles are used in LCD screens to control the direction of light, and in polarized sunglasses to reduce glare.

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